If you are getting this error on a RPI2 - The following solution worked for me.
AttributeError: 'module' object has no attribute 'GPIO'
In the webiopi-0.7.X directory is the /python directory:
1.CD into /python/native/
Edit the file:
change "BCM2708" to "BCM2709"
2.While still in python/native/
Edit the file gpio.c
change #define BCM2708_PERI_BASE 0x20000000 to
#define BCM2708_PERI_BASE 0x3f000000
3.Head back out to your root webiopi-0.7.X directory and run setup.sh again.
Hope this helps.